[PATCH 16/39] virtio_scsi: use cmd_size

Christoph Hellwig
2014-03-17T13:27:49Z

[-- Attachment #1: 0016-virtio_scsi-use-cmd_size.patch --]
[-- Type: text/plain, Size: 3489 bytes --]

Taken almost entirely from Nicholas Bellinger's scsi-mq conversion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
drivers/scsi/virtio_scsi.c | 25 +++++++------------------
include/scsi/scsi_cmnd.h | 9 +++++++++
2 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 16bfd50..5ec4a73 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -204,7 +204,6 @@ static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
set_driver_byte(sc, DRIVER_SENSE);
}

- mempool_free(cmd, virtscsi_cmd_pool);
sc->scsi_done(sc);

atomic_dec(&tgt->reqs);
@@ -279,8 +278,6 @@ static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)

if (cmd->comp)
complete_all(cmd->comp);
- else
- mempool_free(cmd, virtscsi_cmd_pool);
}

static void virtscsi_ctrl_done(struct virtqueue *vq)
@@ -496,10 +493,9 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
struct virtio_scsi_vq *req_vq,
struct scsi_cmnd *sc)
{
- struct virtio_scsi_cmd *cmd;
- int ret;
-
struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
+ struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
+
BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);

/* TODO: check feature bit and fail if unsupported? */
@@ -508,11 +504,6 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
dev_dbg(&sc->device->sdev_gendev,
"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);

- ret = SCSI_MLQUEUE_HOST_BUSY;
- cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
- if (!cmd)
- goto out;
-
memset(cmd, 0, sizeof(*cmd));
cmd->sc = sc;
cmd->req.cmd = (struct virtio_scsi_cmd_req){
@@ -531,13 +522,9 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,

if (virtscsi_kick_cmd(req_vq, cmd,
sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
- GFP_ATOMIC) == 0)
- ret = 0;
- else
- mempool_free(cmd, virtscsi_cmd_pool);
-
-out:
- return ret;
+ GFP_ATOMIC) != 0)
+ return SCSI_MLQUEUE_HOST_BUSY;
+ return 0;
}

static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
@@ -683,6 +670,7 @@ static struct scsi_host_template virtscsi_host_template_single = {
.name = "Virtio SCSI HBA",
.proc_name = "virtio_scsi",
.this_id = -1,
+ .cmd_size = sizeof(struct virtio_scsi_cmd),
.queuecommand = virtscsi_queuecommand_single,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,
@@ -699,6 +687,7 @@ static struct scsi_host_template virtscsi_host_template_multi = {
.name = "Virtio SCSI HBA",
.proc_name = "virtio_scsi",
.this_id = -1,
+ .cmd_size = sizeof(struct virtio_scsi_cmd),
.queuecommand = virtscsi_queuecommand_multi,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index dd7c998..e016e2a 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -133,6 +133,15 @@ struct scsi_cmnd {
unsigned char tag; /* SCSI-II queued command tag */
};

+/*
+ * Return the driver private allocation behind the command.
+ * Only works if cmd_size is set in the host template.
+ */
+static inline void *scsi_cmd_priv(struct scsi_cmnd *cmd)
+{
+ return cmd + 1;
+}
+
/* make sure not to use it with REQ_TYPE_BLOCK_PC commands */
static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
--
1.7.10.4